Best Whirlwind armament layout to fight Japanese fighters and bombers?

[A.G. Williams]

How about just four .303 in the nose and tons of ammunition? The concentrated fire of four .303 should kill anything flying in 1940.

In practice, the .303 MGs proved disappointing in the BoB, which is why the RAF was so desperate to fit cannon even before they were ready. Luftwaffe bombers made it back to base with as many as 300 bullet holes in them.

 

[PAT303]

In practice, the .303 MGs proved disappointing in the BoB, which is why the RAF was so desperate to fit cannon even before they were ready. Luftwaffe bombers made it back to base with as many as 300 bullet holes in them.

The Luftwaffe lost 2376 aircraft in the BoB mostly to .303 armed fighters, the RAF lost 1250 aircraft to mostly cannon armed fighters.

 

[PAT303]

No need for changing the goal post, you didn't asked for ammo supply (Oerlikon was offering belt-fed cannons for RAF years before ww2; Shvak was belt-fed) or firing rates to match LMGs (cannons have shells that offer order or two of magnitude better effect on target than LMGs). You claimed that there were no reliable cannons (and HMGs) in 1940 - and that was not the case.

The most common cause of jamming in both the .50 Browning and virtually all the cannons was caused by the ammunition belt, if belt felt cannons worked the British German and Japanese armed forces would have used them, like I have already said, the MG FF/M wouldn't even work with the drum. The RAF was doing trials as far back as 1937 to replace the .303's but couldn't get any of the HMG or cannons, not to mention their ammunition to work reliably enough, stick to the .303's but fast track cannon development

 

[A.G. Williams]

The Luftwaffe lost 2376 aircraft in the BoB mostly to .303 armed fighters, the RAF lost 1250 aircraft to mostly cannon armed fighters.

More analysis needed to take a range of factors into account (no doubt there have been BoB comparisons done elsewhere on this forum). For example, the RAF planes were mostly agile fighters which were hard to hit, the Luftwaffe mainly bombers, slower and easier targets. The Luftwaffe fighters' cannon were also relatively low-velocity with different ballistics from their MGs (of which they had only two).

 

[A.G. Williams]

The most common cause of jamming in both the .50 Browning and virtually all the cannons was caused by the ammunition belt, if belt felt cannons worked the British German and Japanese armed forces would have used them, like I have already said, the MG FF/M wouldn't even work with the drum. The RAF was doing trials as far back as 1937 to replace the .303's but couldn't get any of the HMG or cannons, not to mention their ammunition to work reliably enough, stick to the .303's but fast track cannon development

The British developed belt-fed cannon as a matter of urgency - they used drum-feeding at first simply because that was all that Hispano-Suiza had developed, so the British had to make do with drums until the Chatellerault belt-feed was available in 1941.

"stick to the .303's but fast track cannon development" was exactly what the British did.

 

[PAT303]

The British developed belt-fed cannon as a matter of urgency - they used drum-feeding at first simply because that was all that Hispano-Suiza had developed, so the British had to make do with drums until the Chatellerault belt-feed was available in 1941.

"stick to the .303's but fast track cannon development" was exactly what the British did.

I always thought the Hispano belt feed mechanism was made by Martin Baker?.

 

[Admiral Beez]

In practice, the .303 MGs proved disappointing in the BoB, which is why the RAF was so desperate to fit cannon even before they were ready. Luftwaffe bombers made it back to base with as many as 300 bullet holes in them.

I was thinking more for this scenario. Four .303 with a generous inclusion of incendiary rounds might do the trick. Did any IJA/N aircraft ever return with 300 bullet holes? I think this unlikely.

 

[PAT303]

More analysis needed to take a range of factors into account (no doubt there have been BoB comparisons done elsewhere on this forum). For example, the RAF planes were mostly agile fighters which were hard to hit, the Luftwaffe mainly bombers, slower and easier targets. The Luftwaffe fighters' cannon were also relatively low-velocity with different ballistics from their MGs (of which they had only two).

I've always thought the ''Luftwaffe bombers flew back to France with up to 300 bullet holes in them'' phrase was silly, B17's B24's Lanc's flew back to England full of 20 and 30mm holes also, 109's and 190's peppered with .50 cal, plenty of planes returned shot to hell yet the .303 always cops the flak.

 

[Shortround6]

I always thought the Hispano belt feed mechanism was made by Martin Baker?.

It may have been made by them and/or final development made by them but the basic design came from France, the Chatellerault feed. The plans were actually gotten out of Paris in May of 1940?

 

[PAT303]

I was thinking more for this scenario. Four .303 with a generous inclusion of incendiary rounds might do the trick. Did any IJA/N aircraft ever return with 300 bullet holes? I think this unlikely.

The trouble is not the guns, the trouble is hitting the target, 7-9 seconds of cannon ammo means 99% of pilots hit nothing but open air, at least the .303's have effective tracer and rounds to burn, 12 guns with every 5th a tracer means at least the pilots see were they are missing which will help them learn to lead the target

 

[PAT303]

It may have been made by them and/or final development made by them but the basic design came from France, the Chatellerault feed. The plans were actually gotten out of Paris in May of 1940?

The British developed belt-fed cannon as a matter of urgency - they used drum-feeding at first simply because that was all that Hispano-Suiza had developed, so the British had to make do with drums until the Chatellerault belt-feed was available in 1941.

"stick to the .303's but fast track cannon development" was exactly what the British did.

Thanks for the info, that's why I like this site.

 

[Shortround6]

I was thinking more for this scenario. Four .303 with a generous inclusion of incendiary rounds might do the trick. Did any IJA/N aircraft ever return with 300 bullet holes? I think this unlikely.

Four .303s is OK but hardly devastating. cutting guns to increase ammo may be counterproductive
.
A Whirlwind with 20mm cannon and drum feeds has about 6 seconds of firing time.
A Whirlwind with 20mm cannon and 120 round belt feeds has about 12 seconds of firing time.
A Whirlwind with twelve .303s and 500rpg has about 25 seconds of firing time.
A Whirlwind with four .303s and 1500rpg has about 1 min and 15 seconds of firing time.

It just has to shoot as each target 3 times longer

Several USN pilots made ace in a day using F6Fs with six .50s with about 30-32 seconds of firing time.

To get 30 seconds of firing time with the guns on target (in effective range) calls for quite a number of minutes of combat time (firing passes) and fuel/engine temperature pilot state may start to become issues.

 

[A.G. Williams]

The trouble is not the guns, the trouble is hitting the target, 7-9 seconds of cannon ammo means 99% of pilots hit nothing but open air, at least the .303's have effective tracer and rounds to burn, 12 guns with every 5th a tracer means at least the pilots see were they are missing which will help them learn to lead the target

The reason that I have a particular fondness for the mid-sized Oerlikon FFL, apart from its light weight, is that the MV was around 750 m/s, about the same as the .303s, which means the trajectories would be very similar. With a mixed cannon/MG armament, it would therefore be possible to have half the .303s loaded with the B. Mk IV (Buckingham) incendiary/tracer which ignited on firing, leaving a smoke trail on the way to the target, the other half loaded with B. Mk VI Dixon/De Wilde incendiaries which flashed on impact with the target, indicating hits. One firing button could operate the MGs, one the cannon. So the pilot would open fire on the target with the MGs, zeroing in with the tracers until the sparkles of hits became visible, then pressing the other button to fire the cannon. That should (in theory anyway) minimise the quantity of wasted cannon ammo.

The Luftwaffe did not have this advantage as their 7.9mm MGs had a high MV, the 20mm MG-FF a relatively low one. This also applied to the IJN fighters with the Oerlikon FF (Type 99-1); they did not introduce the FFL (99-2) until later.

 

[Peter Gunn]

What about 6 or 8 .303's? Like Beez said, I doubt any Japanese aircraft except a large flying boat ever came home with 300+ bullet holes in it, especially if incendiary rounds are plentiful.

 

[tomo pauk]

The most common cause of jamming in both the .50 Browning and virtually all the cannons was caused by the ammunition belt, if belt felt cannons worked the British German and Japanese armed forces would have used them, like I have already said, the MG FF/M wouldn't even work with the drum. The RAF was doing trials as far back as 1937 to replace the .303's but couldn't get any of the HMG or cannons, not to mention their ammunition to work reliably enough, stick to the .303's but fast track cannon development

MG FFM certainly worked.
'If the belt fed cannons worked' - they worked, too, once belt feed was designed and produced. British, German and Japanese forces certainly used belt-fed cannons.
That RAF had no working cannons in 1939 was RAF's problem, unfortunately they didn't make a deal with Swiss in 1st half of 1930s as the French and Germans did.

 

[A.G. Williams]

Four .303s is OK but hardly devastating. cutting guns to increase ammo may be counterproductive
.
A Whirlwind with 20mm cannon and drum feeds has about 6 seconds of firing time.
A Whirlwind with 20mm cannon and 120 round belt feeds has about 12 seconds of firing time.
A Whirlwind with twelve .303s and 500rpg has about 25 seconds of firing time.
A Whirlwind with four .303s and 1500rpg has about 1 min and 15 seconds of firing time.

It just has to shoot as each target 3 times longer

Several USN pilots made ace in a day using F6Fs with six .50s with about 30-32 seconds of firing time.

To get 30 seconds of firing time with the guns on target (in effective range) calls for quite a number of minutes of combat time (firing passes) and fuel/engine temperature pilot state may start to become issues.

Early in WW2 RAF combat reports indicated that one aircraft was shot down for every 4,500 rounds of .303 fired. Even before the war, in November 1938, tests had already produced the conclusion that the introduction of a weapon of at least 20mm calibre was urgent.
(both from Flying Guns WW2)

 

[PAT303]

Early in WW2 RAF combat reports indicated that one aircraft was shot down for every 4,500 rounds of .303 fired. Even before the war, in November 1938, tests had already produced the conclusion that the introduction of a weapon of at least 20mm calibre was urgent.
(both from Flying Guns WW2)

That would be all rounds fired including the misses, there's not an aircraft made anywhere in the world that would be in a flyable state after having 4,500 AP and incendiary .303's fired into it.

 

[PAT303]

The reason that I have a particular fondness for the mid-sized Oerlikon FFL, apart from its light weight, is that the MV was around 750 m/s, about the same as the .303s, which means the trajectories would be very similar. With a mixed cannon/MG armament, it would therefore be possible to have half the .303s loaded with the B. Mk IV (Buckingham) incendiary/tracer which ignited on firing, leaving a smoke trail on the way to the target, the other half loaded with B. Mk VI Dixon/De Wilde incendiaries which flashed on impact with the target, indicating hits. One firing button could operate the MGs, one the cannon. So the pilot would open fire on the target with the MGs, zeroing in with the tracers until the sparkles of hits became visible, then pressing the other button to fire the cannon. That should (in theory anyway) minimise the quantity of wasted cannon ammo.

The Luftwaffe did not have this advantage as their 7.9mm MGs had a high MV, the 20mm MG-FF a relatively low one. This also applied to the IJN fighters with the Oerlikon FF (Type 99-1); they did not introduce the FFL (99-2) until later.

I suggested the very same thing and got roasted for it, if I flew in WW2 I'd have my Spit set up exactly as you described, use short bursts from the .303's until I saw the flash then toggle the switch and let the SAPI's go to work.

 

[PAT303]

MG FFM certainly worked.
'If the belt fed cannons worked' - they worked, too, once belt feed was designed and produced.

Belt feed did indeed work yes but not till years later, hence the reason the A6M Bf109 Spit MkV all used drums.

 

[tomo pauk]

Belt feed did indeed work yes but not till years later, hence the reason the A6M Bf109 Spit MkV all used drums.

When belt feed was available, people used it. Nobody was using it before it was available.